Paraquat: An Oxidative Stress Inducer

Lascano, Ramiro; Muñoz, Nacira; Robert, Germán; Rodríguez, Marianela; Melchiorre, Mariana; Trippi, Victorio S.; Quero, Gastón

doi:10.5772/32590

Cited by 34 publications

(29 citation statements)

References 90 publications

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“…To verify if annexin-mediated drought tolerance influenced light responses, we analyzed the effect of the photosensitizer MeV on transgenic plants overexpressing STANN1. MeV induces oxidative stress, which enables studies of oxidative tolerance and stress cross-tolerance in plants [ 68 ]. MeV induces an oxidative burst by accepting electrons from PSI and transferring them to molecular oxygen, which results in massive H 2 O 2 accumulation in light and generates oxidative stress in chloroplasts.…”

Section: Resultsmentioning

confidence: 99%

Potato Annexin STANN1 Promotes Drought Tolerance and Mitigates Light Stress in Transgenic Solanum tuberosum L. Plants

et al. 2015

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Annexins are a family of calcium- and membrane-binding proteins that are important for plant tolerance to adverse environmental conditions. Annexins function to counteract oxidative stress, maintain cell redox homeostasis, and enhance drought tolerance. In the present study, an endogenous annexin, STANN1, was overexpressed to determine whether crop yields could be improved in potato (Solanum tuberosum L.) during drought. Nine potential potato annexins were identified and their expression characterized in response to drought treatment. STANN1 mRNA was constitutively expressed at a high level and drought treatment strongly increased transcription levels. Therefore, STANN1 was selected for overexpression analysis. Under drought conditions, transgenic potato plants ectopically expressing STANN1 were more tolerant to water deficit in the root zone, preserved more water in green tissues, maintained chloroplast functions, and had higher accumulation of chlorophyll b and xanthophylls (especially zeaxanthin) than wild type (WT). Drought-induced reductions in the maximum efficiency and the electron transport rate of photosystem II (PSII), as well as the quantum yield of photosynthesis, were less pronounced in transgenic plants overexpressing STANN1 than in the WT. This conferred more efficient non-photochemical energy dissipation in the outer antennae of PSII and probably more efficient protection of reaction centers against photooxidative damage in transgenic plants under drought conditions. Consequently, these plants were able to maintain effective photosynthesis during drought, which resulted in greater productivity than WT plants despite water scarcity. Although the mechanisms underlying this stress protection are not yet clear, annexin-mediated photoprotection is probably linked to protection against light-induced oxidative stress.

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Section: Resultsmentioning

confidence: 99%

Potato Annexin STANN1 Promotes Drought Tolerance and Mitigates Light Stress in Transgenic Solanum tuberosum L. Plants

et al. 2015

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“…PCC 7120 pBG2165 to MV and H₂O₂ MV was selected as model pollutant to detect O2 − since its mechanism of action, as continuous source of O2 − , is well known. This herbicide affects directly photosystem I intercepting the electrons which go from ferredoxin to NADP⁺ (Lascano et al, 2012). Therefore, the response of Nostoc sp.…”

Section: Resultsmentioning

confidence: 99%

“…MV is an herbicide widely used in Europe until 2007, when the European Union banned its use because of its high toxicity. MV acts directly on photosynthesis at the level of photosystem I by intercepting electrons ranging from ferredoxin to NADP + (Lascano et al, 2012). Because its action is specific to the photosynthetic machinery, and it is directly linked to the production of O2 − , it is considered a model pollutant of oxidative stress in photosynthetic organisms (Lascano et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…MV acts directly on photosynthesis at the level of photosystem I by intercepting electrons ranging from ferredoxin to NADP + (Lascano et al, 2012). Because its action is specific to the photosynthetic machinery, and it is directly linked to the production of O2 − , it is considered a model pollutant of oxidative stress in photosynthetic organisms (Lascano et al, 2012). The characterization of sensitivity profile was performed with increasing concentrations of MV in cyanobacterial culture medium AA/8 + N as well as in real waters spiked with MV.…”

Section: Introductionmentioning

confidence: 99%

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Two novel cyanobacterial bioluminescent whole-cell bioreporters based on superoxide dismutases MnSod and FeSod to detect superoxide anion

et al. 2018

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This work describes the construction of two novel self-luminescent bioreporter strains of the cyanobacterium Nostoc sp. PCC 7120 by fusing the promoter region of the sodA and sodB genes (encoding the superoxide dismutases MnSod and FeSod, respectively) to luxCDABE from Photorhabdus luminescens aimed at detecting pollutants that generate reactive oxygen species (ROS), particularly O. Bioreporters were tested against methyl viologen (MV) as the inducer of superoxide anion (O). Both bioreporters were specific for O and Limits of detection (LODs) and Maximum Permissive Concentrations (MPCs) were calculated: Nostoc sp. PCC 7120 pBG2154 (sodA) had a range of detection from 400 to 1000 pM of MV and for Nostoc sp. PCC 7120 pBG2165 (sodB) the range of detection was from 500 to 1800 pM of MV after 5 h-exposure. To further validate the bioreporters, they were tested with the emerging pollutant Triclosan which induced bioluminescence in both strains. Furthermore, the bioreporters performance was tested in two real environmental samples with different water matrix complexity, spiked with MV. Both bioreporters were induced by O in these environmental samples. In the case of the river water sample, the amount of bioavailable MV as calculated from the bioreporters output was similar to that nominally added. For the waste water sample, the bioavailable MV concentration detected by the bioreporters was one order of magnitude lower than nominal. These differences could be due to MV complexation with organic matter and/or co-occurring organic contaminants. These results confirm their high sensitivity to O and their suitability to detect oxidative stress-generating pollutants in fresh-waters.

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“…Cysteine plays a major role in maintaining an intracellular reducing environment, thus protecting against oxidative stress ( 48 ). We treated E. coli carrying the wild-type or P238L mutant RhlB with the oxidative stress inducers H 2 O 2 and PQ (an agent that diverts electrons from NADH or NADPH to molecular oxygen to generate a flux of superoxide ( 49 )) and examined growth ability. We observed improved survival in the P238L mutant, suggesting improved oxidative stress resistance ( Fig.…”

Section: Resultsmentioning

confidence: 99%

The Protein Interaction of RNA Helicase B (RhlB) and Polynucleotide Phosphorylase (PNPase) Contributes to the Homeostatic Control of Cysteine in Escherichia coli

Tseng

Chiou

Gogiraju

et al. 2015

Journal of Biological Chemistry

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PNPase, one of the major enzymes with 3′ to 5′ single-stranded RNA degradation and processing activities, can interact with the RNA helicase RhlB independently of RNA degradosome formation in Escherichia coli. Here, we report that loss of interaction between RhlB and PNPase impacts cysteine homeostasis in E. coli. By random mutagenesis, we identified a mutant RhlBP238L that loses 75% of its ability to interact with PNPase but retains normal interaction with RNase E and RNA, in addition to exhibiting normal helicase activity. Applying microarray analyses to an E. coli strain with impaired RNA degradosome formation, we investigated the biological consequences of a weakened interaction between RhlB and PNPase. We found significant increases in 11 of 14 genes involved in cysteine biosynthesis. Subsequent Northern blot analyses showed that the up-regulated transcripts were the result of stabilization of the cysB transcript encoding a transcriptional activator for the cys operons. Furthermore, Northern blots of PNPase or RhlB mutants showed that RhlB-PNPase plays both a catalytic and structural role in regulating cysB degradation. Cells expressing the RhlBP238L mutant exhibited an increase in intracellular cysteine and an enhanced anti-oxidative response. Collectively, this study suggests a mechanism by which bacteria use the PNPase-RhlB exosome-like complex to combat oxidative stress by modulating cysB mRNA degradation.

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Paraquat: An Oxidative Stress Inducer

Cited by 34 publications

References 90 publications

Potato Annexin STANN1 Promotes Drought Tolerance and Mitigates Light Stress in Transgenic Solanum tuberosum L. Plants

Potato Annexin STANN1 Promotes Drought Tolerance and Mitigates Light Stress in Transgenic Solanum tuberosum L. Plants

Two novel cyanobacterial bioluminescent whole-cell bioreporters based on superoxide dismutases MnSod and FeSod to detect superoxide anion

The Protein Interaction of RNA Helicase B (RhlB) and Polynucleotide Phosphorylase (PNPase) Contributes to the Homeostatic Control of Cysteine in Escherichia coli

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